Receiving apparatus for electric telegraphs and electric selective systems.



w. I; News. RECEIVING APPARATUS FOR ELECT'RiC TELEGRAPHS ANDv ELECTRICSELECTIVE SYSTEMS.

. Arrucmqu un 115.1913; I 1,205,460.. Patented Nov'q2l, 1916.

F w. J. wows,

RECEIVING-APPARATUS FOR'ELECTR-IC TELEGRAPHS AND morass sazcnvn svsmvlsrmenia FILED MAY 5. 19:3.

1,205,460. .4 7 Patented Now-21 1916.

2 swim-swam 2.

UNITED TAT S PATENT OFFICE.

WILLIAM JOSEPH LYONS,

OF DUBLIN, IRELAND.

RECEIVING APPARATUS FOR, ELECTRIC TELEGRAPHS AND ELECTRIC SELECTIVE Toall m/wmit may concern Be it known that I, VILLIAM Josnrn LYoxs, a subect of the King of Great Britain and Ireland, residing at Dublin,

lreland, have invented Improvements in Receiving Apparatus for ElectricTelegraphs and Electric Selective Systems, of which the following is aspecification.

This invention relates to receiving apparatus of the selective typewhereby a calling or other device can be automatically brought intoaqtionat any particular station or place after the complete reception,but not otherwise, at such station or place of a predeterminedtelegraphicsignal or message transmitted by wireless or other method.

The present invention relates to improvements in selective receivingapparatus of the type referred to and comprises for the purpose ofcontrolling the working of the call or other device (hereinafterreferred to as the call device) a novel arrangement of primarycontrolling means subject to the electric signals received and'workingon a new principle whereby inter alia the construction of the selectiveapparatus can be' simplified, as compared with previously proposedarrangement of such apparatus, and

whereby the range and exactness of the selectivitv obtainable insignaling can' be improved. I

Broadly, receiving apparatus of the type referred or constructedaccording to the present invention, comprises a controlling lever or arm(hereinafter usually referred to as the arm or controlling arm, arrangedto be moved either directly or indirectly through a re1ay, by theimpulses corresponding to the received electrlc signal, and a x40sin-face which is set in motion on the receipt of the first impulse andwhich then, independentlyof any action of the arm, con-.

tmues 1n motion in a direction at right angles or substantially so, tothe movements of the controlling end of the said arm which perpendicularto the said bined with the movements of the said end of the arm beingsuch that the aforesaid end of the 'armiwill, during the reception of athen of the call device,

of single electric sequence.

face, so long as the SYSTEMS,

. I I 1 ,205,460. Specification of Letters Patent. Pat t d X 21 1916Application filed May 5, 1913. Serial No. 765,560. I w i 4 signal, becaused to come into 'contactlfiwith a definite portion or with definiteportions of the said surface. The, moving surface is so formed orconstituted with reference to the movements of the said end of the armthat result from the reception of the par-- ticular signal which'is tocause the operathat this device will not be brought into operation ifthe end of the arm should make contact with portions of the movingsurface with which it would not make contact if the prearranged signalwere received.

Apparatus constructed and operating as just described can be used toeffect selective operation of'a callt g device in response tosignals ofthe type co isisting of a definite number of electric impulses of thesame duration of activity separated by prearrangedintervals of coda]inactivity; to sigpulsesshort and long, as in the. Morse system of apro-arranged number, sequence and rate, and to signals which mightconsist impulses of prearranged duration of activity, or of combinationsof such impulses of prearranged number and Furthermore, by means of thenew apparatus a call device designed to be brought into operation by aparticular signal, for example S O S on the Morse code, will not be putinto. operation by or during the reception of the electric impulses}corresponding to a signal, as for examplei S O S O on' the reception ofany other signal, which, in part, involves theaforesaidparticular-signal for which theapparatus is arranged.

The construction and arrangement of the controlling. arm and movablesurface may conveniently be such that when the apparatus is inaction thearm will close an electric circuit during themovement of the sursignalbeing received corresponds to the prearranged code and is not followedwithin a given time by any other effective impulses; or it may be suchthat the arm will be prevented from clo ing an electric of the surfaceMorse code, or during the 8'5 l circuit during the movemen Y so long asthe s gnal. being," D0

received corresponds to the prearranged code and is not followed withina given time by any other elleetlve impulses. In an arrangemel'lt ofthis kind the arm may, forapparatus is designed to respond, being ar-Fig. 1.

ranged lengthwise of the surface and composed either of conductingmaterial, or of insulating material, or it may-be of insulated material(hereinafterincluded in the term insulating material) and having ad-:jfiCGHt-lillBI'BtO in the one case insulating material and in theothercase conducting material so that the electric circuit controllingthe call device will either be kept closed, or be kept open, as the casemay be, Whale the electric sign al being received corresponds to thepro-arranged code signal, but will either be opened or be closedrespectively by the-arm moving onto the insulating material, or" on tothe conducting material as the case may be, in the event of a differentsignal being received; g

Receiving apparatus of the kind referred to, designedto operate in themanner set forth, can beconstructed in variousforms. In the accompanyingdrawings, Figure l is a diagram of one' constructional arrangementaccording to the invention. Fig. 21s a development of part of Fig. 1 andFig. is'a part development of a modification. Fig. 4 is an elevation ofa disk foruse in another arrangement of the hind showyn in Fig. is aperspective view of an endless band device also adapted to be used in amodification of Fig. 1. Figs. 6, 7 and 8 are diagrains illustrative ofother constructional arrangements according to the invention. 9 is a.diagram of still another construction and arrangement. 7 In, Fig. 1there is employed a pivoted spring actuated metallic arm a thatis underthe control of an electro-magnet I) the circuit of which is controlledby a relay responsive to long and short telegraphic signals transmittedby Wireless ,or other methods, the said arm a being arrangedto act atits free end against a drum (Z adapted to be rotated by suitablemechanism, such as is hereinafter described. The drum has a peripheralsurface of insulating material in w1'1ieh is laid, so as to be flushtherewith, a

strip 0 of conducting material, such as metal,

of T a zigzag form corresponding to, the

path that the free end of the arm will trace out on the drum as a resultof the particular rate of motion of the drum and the 0sci1- and numberof the electric impulses corresponding to the special telegraphic signalor message for which the apparatus is designed to respond. The arm a andconducting strip e are arranged to form part of an electric circuitincluding an electro-magnet j that controls the lateral position of amovable member 9 of a circuit-closing device h. The member {I is engagedby a lever 1 arranged to be moved against the action of a spring 37 orother restoring means, by the electro-magnet f, when this is energized,so as to enter into the path of v, a pin In or equivalent device that isset in operation withthe setting into operation of the drum a? by theinitial movement of the arm a and thus as long asthe electro-magnet f iskept energized to gradually bring the said memher g into a position toclose, through the device it, the circuit of the calling or otherdevice, forexample an electric bell to, when 'orstrip e and the circuitof the said electromagnet f will be broken and the movable a member gcontrolled thereby returned to an 1n1t1al and inoperative position, sothat the calling or other device cannot then he.

brought into operation.-

As shown in Fig. 2,'which is a development of'parts'of the drum cl,hereinafter more'particularly referred to the end n, of the metal strip6 is soformed and arranged, as by lengthening it in the circumferentialdirection of the drum, that in' the event of the impulses correspondingto a particular signal or messagebeing followed Within the predeterminedtimeby another impulse, the circuit ofthe said electromagnet f, will bebroken and the movable member controlled thereby returned to an initialand inoperative position before the circuit of the calling device h,.can be completed, so that the into operation.

In the. example, the arrangement isadapted to respond to the signal S OS adopted in Wireless telegraphy as the distress call'for ships,

Instead of providing the drum with an insulatcdfsurface and a strip 6 ofmetal of the form mentioned, the surface of the drum (1 a may be oimetal and be provided, as shown;

for example in Fig. 3, which is a developed view of part of the drum,with pieces 2' of insulating material at parts thereof Where the freeend of the arm would necessarily pass uponthe receipt of impulses notcorresponding in sequence, rate or number to that of the requiredspecial signal or message, so as to break thecircuit of theelectromagnet f; (Fig. 1) controlling the motion of the movable'member gof the circuit closing device nd cause such member to move 5 into aiosition in which'it is inoperative and wil continue to be inoperativeuntil the apparatus isiagain in aniuitial condition and is again set inaction for receiving another message.

Ihe zig-nag shaped piece e of metal, or the group of pieces i ofinsulating materlal, carried by the drum (l and correspondingto inspecial signal or message, may, as 1s mtended in Fig. 1, be arranged toextend around the Whole of the circumference of the drum, or nearly so,so that one cycleof operations will take place for each rotation of thedrum. Orga number of pieces 6 of metal, or gro'ii s of pieces i ofinsulating .material, may arranged in series around the drum so that inthis-case two or more cycles of operations will take place for each rotaion of the drum, the apparatus being in an initial or receptivecondition at a number of definite and equally spaced points around thedrum.

to show an arrangement in which two cycles per revolution are obtained.

In lieu of a. drum, a rotary disk 0, Fig. 4,

SO-tor anihdless traveling belt 7), Fig. 5, may be used, and for thezig-zag shaped piecee of metal, or the pieces 5 of insulating material,the surface of the drum or equivalent may be otherwise adapted to permitthe arm a to move into a position to close the circuit of theeiectro-magnet f and to move the arm and break the circuit when thesequence, rate or number of the impulses departsfjfromthaf'corresp'onding to the special message or 40 signal for which the a'iparatus is designed.

, The starting of the drum or equivalent and associated mechanism on thereceipt of the first impulse of a signal or message can be effected invarious ways, as by the pivot- 45. cd arm a being withdrawn from a stop'1'.

Thus Fig. 2 is intended or one of a number of stops 2", on the drum -17,or equivalent, or by its releasing abrake on the driving mechanism ofthe drum; or

the-starting of the driving inecluinisni may be effected byelectromagnetic means, as

will be described hereinafter.

The arrangements thus far-describedillustrate some ways of carryingoutthe invention which may however be modified.

The closing. of'the circuit which operates the electricbell m or otherdevice depends, in the arrangements described with reference toFigs. 1to 5, on "the free end of the arm a being made to sustain a contact withthe metallic portion of the surface of the drumgand thus to keep closedan electric circuit until the complete reception of theparticularmessage has been effected. when such is the case the.mechanical device comprising the parts f, g, h, j, :1, L, may be revthedrum until a contact n:- is reached.

placed by an arrangement such as is diagrammatically shown in Fig. 6where tlic developed surface of the drum with the pieces 6 of insulatingmaterial is arranged for the signal S O S. One end of the arm 11 7a isbifurcated, asat a, (L2 and in the initial position both of these ends aand a are in contact with the metal stop a which is insulated from themetallic surface r,- of the. drum. A contact key if is actuated by theelectromagnet'f and the battery u is connected as shown. \Vhen the firstelectric. impulse received causes the electromagnet b to move the arm a,the circuit through the. electromagnet f is completed by the bifur- 3ocation at the end of the urin (1. connecting the stop a for 2 short timcwith the conducting surface a of the drum. (ontact bat tween t and r ismade when the clcctrd" magnet is thus energized and the circu'it' af gsthrough such electromagnct is niaintaincl' l' f closed through thiscontact as long as the? enda or r1. of the arm (I is in contact with thesurface of the drum r]. It is arranged that thecnd of shall be incontact with the N drum 1! before the end (1, leaves the stop a and thatthe end o makes contact with the drum (1 before the end 0. is put out ofcontact with the latter, In the subsequent path along the drmn ,-it canbe arranged that only the end rt touches thesurfai-e of If. the arm a isinfluenced by impulses in quencc, rate and number corresponding to thesignal or mesmge for which the drum is arranged, the end 1/ continues incontact with r4 and the electro-magnct f remains energized. \Vhen thecomplete signalhas been received and is not followed by another impulscwithin a predetermined time, the end' (1. of the arm (I. engages thecontact 1v before the end (1. leaves the conducting I path I; at .r sothat when the latter cven't happens, current passing throughf, r. t, aand 'w is .made to operate the circuit closer of a battery 1 andcausethe continurms ringing of an electric bell m or-otbcr device. Tfduring the reception of the signal or message the arm end a leaves theconducting path a on the drum the circuit through f is broken, and thekey I rccedes'from thrcontact n, thereby rendering the mechanisminoperative until the apparatus is again in its initial condition and isagain set -in action for another signal or message. An arrangement ofthis character is applicable also where the selective operation of thecalling or other device is arranged to depend on the free end of theselective arm rt not making contact with a conducting strip or surfaceon the drum.' Thus, in the arrangement shown in Fig. 7, the pieces 1,which 'are in metallic communication with each other, are connected,thriiiiglra cons" ductor 2 t me pole ofa-"battery 8. In ala melectricalinitial position, the free end of the selective arm a, which isbifurcated, as in Fig. 6, is in contact with the metallic drum stop Onthe reception of the first impulse the said arm end connects themetallic stop 3 to a contact piece 4, the said stop 8 and contact 4being insulated from the contacts 1, and contact 4 being connected tothe other pole of the battery 8. A. current consequently flows throughhalf the winch ing of the electromagnet Thus energized, theelectro-magnet closes the gap between two contacts-5 and 6 and thecurrent due to the bridging of the stop 3 and contact 4 is now replacedby current flowing through the contacts 5. and 6 across a switch 7.

If during the reception of the impulses the arm end a, which may bearranged to clone touch the drum, deviates from the path that accordswith a particular signal or message, the said endt'I- will be put intoconnection with conductor 2 through one oft-he piecesof metal Land, aswill be seenjr'i'mm the figure, current from the battery Elfiiiilldivide at the point 9 part passing through what in the illustration isthe lower half of the solenoid f to the point 9 and part passing throughthe conductor 2, contact 1 and arm a, (1: and through the upper half ofthe solenoid fin the reverse direction to that in the lower halfito thepoint 9 and thence through the contacts 5 and 6' and switch 7 to theother pole of the battery. In this way the action ofthe solenoid isneutralized. The neutralization of the solenoid f releases contact 5from contact 6 and the system becomes inoperative until the mechanismreturns to its initial condition and is again set in action to receiveanother signal or message. If the so queues... rate and number of theimpulses correspond to those of the signal. or message for which thesurface of the drum is arranged, the circuit will continue closed at 5,6. After the complete receptionofthe signal or message, the free end oflever a, via, the ends a? and (it of the bifurcation will reach a. partof the drum where, as in the case of Fig. 6, by means of the bridging ofcontacts in the drum the current may be defiected through the calloperating device, or, as represented in Fig. 7, spin 10 on the drum atthe end of the path may be made to open the switch at 7 and deflect thecurrent that passes-.through 5,6 so as to cause it to flow through andstart the continuousringin'g bell m or other device.

The method of this invention can obviously be applied so as to make onemechanism selectively respond to two or more different signals ormessages and close a particular circuit'and thus operate a particularbell or indicator or other device in response to each message. Thus, onthe same drum d two or more strips 0 of material may be inlaid side byside as shown in Fig. 9, or the paths for two or more difterent signalsmay be otherwise defined as already described by two or more series ofpieces of material '5 (Figs. 3 and 6) laid into the surface of the drumas already described. A separate movable arm a is provided for each.message and" otherwise the arrangements may be of the type alreadydescribed.

Instead of the apparatus being used for bringing into action an audiblecalling device, for example an electric bell m, as for instance when theapparatus is to be used for receiving danger signals or other specialsignals sent by wireless or other telegraphic method, it may be used forsome other per poses, as for example for firing a particular mine, gun,rocket or the like.

Signals other than dots and dashes of the Morse code a signal consistingof a single sustained impulse of predetermined du- -i-at1on, -or asignal consisting ot a predetermine'd number and. sequence 'of impulseseach being sustained forv a predetermined period, the several periods inthe latter case being equal or different, may be adopted,

the invention permitting such signals to be treated selectively. Thesignals may be transmitted automatically at a definite rate, or simplesignals, such. as the dot, dash, dotdash or'dash-dot may be transmittedwith-. out automatic mechanism.

In aparatus such as hereinbefore described the drum 0? or equivalentsurface may be driven, by a clock-work or electric motor (1 (Fig. l),the fixing of the proper speed beingregulated in known or suitable 1nan-The drum or equivalent surface may be permanently coupled to the drivingmechanism, in which case the starting and stopping of the drum isdetermined by the starting and stopping of the mechanism, or,alternatively, the driving mechanism may be run continuously and thedrum or mov able surface may be connected theretoand disconnectedtherefrom at starting and stopping respectively by the action of afriction device or by a mechanical or mag netic clutch. I I

The starting of the drum or driving mechanism on the receipt of thefirst impulse, of continuing the motion, and of suddenly stopping it atthe proper time can be effected in various waysother than by the use. ofone or more stops as herein- Fig. 8 shows dies by suitably controlledclockwork, '51 being a disk connected tothe most rapidly moving part ofthe clock mechanism another element of which is shown at 512. 53 is abrake lever that normally holds the mechanism stationary in its zero, orinitial position under the action of an adjustable spring 54; a slightpressure of which suffices owing to the. high gearing of the mechanism.55 is an electromagnet the core 56 of which'is' arranged to'pull backthe brake lever 53 against the action of the spring 54, when energizedby current from a battery 57.

metal contacts arranged in and fiush with thesurface of the drum andconnected to the-"opposite poles of the battery. The core 56 isconnected to the same pole of the battery as the contact 58 and makesmetallic contact through' a thin layer of silver or brake lever 53 whenit The oscillating arm a is electrically connectedthroug-h a conductor60 to the brake lever 53 and through a conductor 61 tonne terminal ofthe coil of the electroniagnet 55 the other terminal of whichisconnected by a conductor 62 to the platinum with the ,same pole of thebattery as contact 59.

Initially, the movable end of the arm a is at a definite position on thedrum, viz.

on contact 59'. On the receipt of the first impulse it moves across thesurface of the drum aid makes connection with contact 58. The circuitthrough the electromagnet 55 is thus made, the brake lever 53 pulledback and the clock mechanism and drum (Z started. The circuit therebymade through the battery 57, conductor 62, the coil of theelectro-ma'gnet 55, conductors 61 and 60,

brake lever 53 and. core 56 is maintained during the subsequent movementof the, drum which is in the direction of the arrow.

the drum is just at the end of its When prearranged course, the contact09- passes under the end of the arm a and the current passing; from onepole of the battery 57' 56 and brake lever 53 inconductor 61, takes amomentary short circuit through the arm a, contact 59 and con.

ductor 62 back to-the battery. The .electromagnet 55 being thusdeenergized the brake lever 53 is thus released and stops the mechanism,the current is automatically cut off and the apparatus left in its tion'ready for another signal. It will be seen that owing to the high gearinof the mechanism and the slow movement of the drum relative to that ofthe disk 51 the gradual stopping of the disk will result in thestoppingof the drum (Z at a very exact 58 and 59 are two insulated zeroposhferred to above, e. g. for starting or stop--' ping an electricmotor, the brake lever 53 being then replaced by a switch, or forcoupling up the drum to a continuously driven mechanism in which casethe brake lever 53 would be replaced by a mechanical or magnetic clutchas already suggested.

\Vh'at I claim is I 1. Electric telegraph, receiving apparatus ofselective type comprising a movable member, means whereby, said movablemember will be set in motion upon the receipt of an electric impulse, asecond movable member adapted to co-actwiththe first mentioned movablemember, electromagnetic means whereby saidsecond movable memberwill beoperated in a variable manner by'the electric impulses received, and insuchmanner that movement of said second'movable member relative to thefirst mentioned movable member will be determined bythe nature of theelectric impulses received, a device to be operated upon the receipt ofa predetermined signal, electric connections and a source of current foroperating sald device, said movable members being arranged to cooperate-Electric telegraph receiving apparatus of selective type comprising anelectric contact device mounted to move to and fro in a -variable mannerand in accordance'\\-'ith the electric impulses received, a rotarycircuit closing device co-acting with said Contact device, means wherebysaid rotary circuit closing device will be set-in motion upon thereceipt of an electric impulse, electrical connections, a call device tobe operatedupon the receipt of a predetermined signal and a source ofcurrent for operating said call device, said contact device and circuitclosing device being arranged to cooperate to close a circuit in saidelectric connections and bring about the operation of said call deviceonly when they occupy certain predetermined relative positions dependingupon the nature ofthe signal for which the apparatus is designed torespond.

3. Electric telegraph receiving apparatus for selective type comprisinga movable circuit controlling surface, means whereby said surface willbe set in motion upon the receipt of an electric impulse, an arm movablein relation to said surface, means under the control of th lflgctricimpulses received adapted to move said arm in relation to and u on saidsurface,.electrical connections contro lid by said relative movementbetween said suradapted to niove said i only mechanism comprising anarm, by said farm W111 be face and arm, and call means adapted tobebrought into action under the control of said electrical connectionsonly upon the arm following a predetermined path relatively to saidsurface and occupying a definite position at the completion ofthetransmission of the'predetermined signal for whicb'the apparatus isdesigned to respond. 4. Electric telegraph receiving apparatus ofselective type comprising a movable circuit controlling surface, means\vhereby'saidsurface will, be set in motion upon the receipt of anelectric impulse, an arm movable in relation to said surface, meansunder the control of the electric impulses received arm transversely tothe direction off movement of said surface and upon said surface,electrical connections controlled by the transverse movement of said armrelatively to said surface and call means adapted to be brought intoaction under the controlof said electrical connections upon the armfollowing a'predetermined path relatively to said surface and nocupying-a definite position at the comple tion of the transmission ofthe predeter mined signal for which the apparatus is designed torespond. i

5. Electric telegraph r of selective type comprising a cuit controllingsurface, means whereby said surface will be set in motion upon thereceipt ceiving apparatus of an elcctg/limpulse, an arm movable inrelation to a and upon saidsurface, means under the control of theelectric impulses receivedadapted tojmove said arm in a to and-frodirection across said surface, said surface being arranged to be set inmotion in a direction'substantially at right angles to the to-and-fromotion of said arm upon the receipt of an electric impulse, electricalconnections controlled by the relative movement between said surface andarm and a call de: vice, the formation of said controlling surface andthe movement of said arm being such that said call device will not bebrought into operation by an electric signal of shorter or longerduration than that for which the apparatus is designed to respond. 6.Electric telegraph receiving apparatus of selective type, comprising adevice to .be operatedonly upon the transmission and 1cception of anelectric signal according to a pro-arranged code, and "mechanism forbringing. said device into operation, said means where-j! moved by thereceived" electric signal, a surface with which such arm coacts, meanswhereby said surface is arranged to be moved substantially at rightangles to that the motion of the operative end of said arm on thereceipt of a signal, said surface after being startedcontinuing itsmotion independently of the arm, and.

movable cirmeans whereby said surface is caused to, at ,start on thereceipt of a signal, said"surface being of a composite nature dependentupon the nature of the signal for which the'appw 'ratus is torespond andsaid arm acting to bring said device into operation only upon 3'0- itsfollowing a predetermined path on said surface corresponding to thepredetermined signal.

I 7. Electric telegraph receiving apparatus of selective type,comprising a device to be To operated onlyupon the transmissionendemiccption of an electric signal according tola pro-arranged codeandmechanism for bring ng said device into ope-ratiomasaid mccha-1115111 comprising a movable surface adapted to tostart traveling; in aparticular direction upon the recelpt of an electric impulse andcarrying a trace of a predetermined signal,

means for permitting said surface to start trai 'ehng upon the receiptof an electric inn pulse, a contact arm and meansresponsive to electricimpulses adapted to displace said contact arm; relatively to said movingsur- 1 face, said arm following said trace and bringing said device intooperationfouly in to the event of the signal sent corresponding to thatfor which the apparatus is designed to respond.

8. Electric telegraph receiving apparatus of selective type, comprisinga member, 9.5g

means whereby said ni'ember'can be started and stopped, a source ofcurrent having one pole in connection with the surface of the saidmember and an arm connected with the other pole whereby said arm can bestarted in synchronism with such member so as to be brought intooperative relationship thereto,

and means whereby said member and arm will malntain a given conditionofan elec- 111E tuic circuit so long only as the relative movementbetween them accords substantially with a predetermined signal code.

9. Electric telegraph'receiving apparatus of selective type, comprisinga member hav-.

111?, a movable surface, means Wherebysaid member can be moved at auniform specd,: an arm adapted to co-act with said surface and meanswhereby said arm is moved in a variable manner in relation to saidsurface 115 under the action of and in accordance with the electricimpulses received. metallic con tact being made between the surface ofthe inember and the arm to complete an electric circuit during someperiod of codal activity.

10. Electric telegraph receiving apparatus of selective type, comprisinga contact body,

means whereby said bodywill be set in 1notion on the receipt at itslocation of a signaling impulse and continue in motion durmg the receiptof a message, a signaling devicc,'an arm arrangeddowdactwith said ofthe: current source, means 100 said fiflntrollingg' surface and Contact(levies: 01- causizlg operation of. said call device, mid cflntrollingsurface and contact device being arrnmged. to prevent the call devicebeing brought into actinn until after a prw determmed time of coda!mactlvwy has elapsed affier the complem receipt of the signal to whichthe apparatus is to respond.

Signed at- The Ruyal Cullege of Science,

.Dubiin, Ireland this twenty-fifth day of 10 Aprii 1913.

WILLIAM JOSEPH LYONS.

Witneses:

WILLIAM. BROWN,

VVILLIAM Doxmln Duucms.

